Sealing and insulating composition



Patented Dec. 28, 1926.

. UNITED. STATES PATENT. OFFICE- HARRY L. GRANT AND WILLIAM R. IABREN,0F TAMAQUA, PENNSYLVANIA, A8- SIGNORS TO ATLAS POWDER COMPANY, OFWILMINGTON, DELAWARE, A CORPORA- TION OF DELAWARE.

SEALING AND INSULATING COMPOSITION.

llo Drawing.

Our invention relates to compositions comprising cumarone resinsand-sulphur or sulphur compounds such as thio-carbanilid, thio-urea,etc., and has for its object to provide a new and more suitabledielectric material for sealing the casings and other protectivecontainers for delicate electrical and mechanical units and containersfor hygroscopic materials. A further object of this invention istoprovide a highly water-proof and dielectric material which will melt andflow free'l at temperatures somewhat higher than the oiling pointofwater enabling it to be moulded or cast in any geometric form withoutthe aid of pressures in excess of the atmospheric pressure. Among theobjects of this invention is to provide a material characterized by easeof compounding and low cost of raw materials.

In carrying out our invention use is made of the cumar or cumaronesulphur mixture for making various shaped articles, wherein acombination of water-proof and dielectric properties is desired. Thearticles to be produced from this material are usually made by pouringthe composition, while in a molten state, into suitable moulds orcavities, thus producing moulded or cast parts. In using the materialfor sealing casings or rotective coverings or containers it is rought toa molten state by heating and when completely molten is poured into thecavity to be sealed. Sulphur is largely used as a sealing material inmany of the arts. However sulphur alone, if cast into a shape,crystallizes as it solidifies, forming a more or less porous and fragilestructure. The addition of finely divided, solid materials, such assand, clay, glass, brick dust, etc., results in the production of a lessporous mass than is produced by the use of sulphur alone. The finelydivided material seems to interfere with the formation of sulphurcrystals. or at least, causes the formation of smaller crystals thanwould otherwise form. By the addition of cumar or cumarone resin to thesulphur, crystallization of the mass is com pletely prevented and ahard, amorphous casting is produced. We contemplate the continued use offinely divided filling materials, when desired, along with the cumarresin, though the omission of these is within the scope of theinvention. A particular use has been made of our improved material forApplication filed June 26, 1925. Serial No. 39,594.

sealing electric blasting cap shells after insertion of the so-calledelectric fuse head or igniting device. Exhaustive experiments have shownthat electric blasting caps sealed with this material are, practicallyspeaking, impervious to moisture. The usual material for filling suchcaps generally consists of sulphur, mixed with a small percentage ofbrick .85 lbs. absolute pressure, for periods of several hours. Resultsof our experiments have shown that the charges in the electric blastingcaps sealed with the cumar-sulphur mixture are not afiected byatmospheric moisture, when protected as described. This is a verydesirable property for it is well known that even traces of moisture inthe charge will greatly reduce the strength of the detonator. Thematerial described above is chemically neutral and inert .toward themetal of the shell; the explosive used for charging, and also the fusehead. For special purposes we may employ compositions comprising sulphurand coal tar resins comparable with the above described cumaroneresin.

The sealing elements made by our improved method may be made by castingthe compositions in place or by mixing the ingredients in a dry stateand fusing them by the application of heat alone, or heat and pressure.

Our improved composition may be used to advantage as a binder in amanner analogous to the use of shellac in chill molding objects, i. e.taking the composition comprising finely divided sulphur-cumar resin andinert filling material, putting it in a hot mold, pressing it to shape,chilling the mold below the solidifying point of the cumar resin andremoving the shaped article from the mold.

It is to be understood that our invention is not limited to the precisecompositions or manner of use set forth in the description, but that itincludes within its scopewhatever changes or variations fairly comewithin either the spirit of the invention or the terms of the appendedclaims.

Having described our invention, what we claim as new and desire tosecure by Letters Patent is 1. The herein described process of making adielectric and water-proof sealing material which consists ofincorporating, into a homogeneous plastic mass only molten sulphur,molten cumar resin and a finely divided filling material all in suchproportions as to produce abody that is solid when cold.

2. A water-proof and dielectric sealing material of the characterdescribed consisting of a body of sulphur and cumarone resin combined insuch proportions that the whole may be rendered plastic by theapplication of heat and moulded or poured while in that condition, thebody becoming hard when cold, and the cumarone resin preventingcrystallization of the sulphur upon cooling of the mass.

3. A water-proof and dielectric sealing material of the characterdescribed consistin wholly of a body of sulphur, a finely divi edfilling material, and cumarone resin combined in such proportions thatthe whole may be rendered plastic by the application of heat andmouldedtor poured while in that condition, the body becoming hard whencold, and the cumarone resin preventing crystallization of the sulphurupon cooling of the mass.

In testimony whereof they afiix their signatures.

HARRY L. GRANT. WILLIAM R. FARREN.

